A novel degradable tricalcium silicate/calcium polyphosphate/polyvinyl alcohol organic-inorganic composite cement for bone filling

In this study, tricalcium silicate (C3S) calcium/polyphosphate/polyvinyl alcohol organic-inorganic self-setting composites were successfully designed. A variety of tests were conducted to characterize their self-setting properties, mechanical properties, degradation properties, and related biological properties. The composite bone cements showed a short setting time (5.5–37.5 min) with a 5:5–6:4 ratio of C3S/CPP to maintain a stable compressive strength (28 MPa). In addition, PVA effectively reduced the brittleness of the inorganic phase. Degradation experiments confirmed the sustainable surface degradation of bone cement. A maximum degradation rate of 49% was reached within 56 days, and the structure remained intact without collapse. Culturing MC3T3 cells with bone cement extracts revealed that the composite bone cements had excellent biological properties in vitro. The original extract showed a proliferation promotion effect on cells, whereas most of the other original extracts of degradable bone cements were toxic to the cells. Meanwhile, extracellular matrix mineralization and alkaline phosphatase expression showed remarkable effects on cell differentiation. In addition, a good level of adhesion of cells to the surfaces of materials was observed. Taken together, these results indicate that C3S/CPP/PVA composite bone cements have great potential in bone defect filling for fast curing.

Design of a prototype bioresorbable tibial implant in a sheep model

The purpose of this study was the design of a prototype calcium polyphosphate tibial implant for implantation into a sheep. In the design, several design parameters were considered: CPP implant structural strength, the maximum allowed micromotion of the structure at the interface with bone and the possibility of the surgeon implementing the necessary geometric changes on the bone elements during implant surgical insertion. A fininte element analysis facilitated the design and allowed for the effects of the various geometric parameters investigated. This analysis was based on a real solid model of the sheep tibial bone based on the CT scans of a five year old sheep, and several were the geometeric parameters investigated. The approach of the finite element analysis was very conservative, in the meaning that the load applied was purposely increased in order to account for any possibly unknown factors that may exist and not implemented in the analysis.

Design of a prototype bioresorbable tibial implant in a sheep model

The purpose of this study was the design of a prototype calcium polyphosphate tibial implant for implantation into a sheep. In the design, several design parameters were considered: CPP implant structural strength, the maximum allowed micromotion of the structure at the interface with bone and the possibility of the surgeon implementing the necessary geometric changes on the bone elements during implant surgical insertion. A fininte element analysis facilitated the design and allowed for the effects of the various geometric parameters investigated. This analysis was based on a real solid model of the sheep tibial bone based on the CT scans of a five year old sheep, and several were the geometeric parameters investigated. The approach of the finite element analysis was very conservative, in the meaning that the load applied was purposely increased in order to account for any possibly unknown factors that may exist and not implemented in the analysis.

The study on calcium polyphosphate/poly-amino acid composite for supportive bone substitute materials in vitro

In addition to the sufficient mechanical strength to burden the force of the human body, the ideal supporting implant material should have bioactivity to stimulate the cells proliferation and differentiation...

INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE CHEMICAL COMPOSITION OF CALCIUM POLYPHOSPHATES FROM PHOSPHORITES CENTRAL KYZYLKUM

The aim of the research was to study the effect of temperature, the ratio of P2O5EPA:P2O5PRM and the duration of calcination on the content of various forms of P2O5 in calcium polyphosphate. The effect of calcination temperature from 150 to 300 °C, the ratio of P2O5EPA:P2O5FRM from 2,15 to 4,50 and the duration of the process from 20 to 120 minutes on the changes in various forms of P2O5 were studied. It was shown that with increasing temperature to 200-250 °C the content of the total (ortho + poly) assimilable form of Р2О5 increases and then decreases, passing through a maximum. The content of assimilable orthophosphates with an increase in the calcination temperature first sharply decreases to a temperature of 200 °C, and then more smoothly changes at temperatures from 200 °C to 300 °C. The content of assimilable polyforms P2O5 is increased independently of the ratio of P2O5EPA: P2O5PRM to a temperature of 200 °C. With a further increase in temperature in calcium polyphosphate with a ratio of P2O5EPA:P2O5PRM equaled to 2,15, the content of the P2O5 poly decreases by 5%, and at higher ratios P2O5EPA:P2O5PRM increases by 5-10% compared to a temperature of 200 °C. Upon reaching a temperature of 300 °C, the content of the P2O5 polyforms decreases on average by 10-20%, independently of the ratio of P2O5EPA:P2O5PRM. With an increase in the calcination duration from 20 to 40 minutes at temperatures of 200 and 240 °C, the content of the total assimilable form of P2O5 significantly increases. A further increase in the duration of calcination does not lead to a significant increase in the assimilable form of P2O5 as at a temperature of 260 °C. The content of the water-soluble form of P2O5 varies from 6,80-17,52% to 24,30-43,43%, regardless of the temperature and duration of calcination of 20-120 minutes